Why is it comforting that God says 'Thou art mine'?

The phrase 'Thou art mine' speaks to the intimate relationship God has with His people. It offers profound comfort, signifying that believers are not only known by God but also cherished and preserved by Him. Within the context of Isaiah 43:1, it reflects God's promises of protection, love, and redemption. This assurance carries believers through life's adversities, reminding them that God watches over them at all times and has the power to save to the uttermost. It emphasizes His commitment that those whom He redeems are forever His.